1. Field of the Invention
The invention relates to a two wire current transmitter where a DC current is controlled by a transmitter to correspond with the magnitude of a value of a parameter to be sensed by a sensing element which may be a temperature sensitive resistor.
2. Prior Art
Two wire current controllers for various sensors and transducers have been developed. A temperature sensor control arrangement is disclosed in U.S. Pat. No. 3,680,384, issued Aug. 1, 1972 which also discloses thermocouple and millivolt inputs. U.S. Pat. No. 3,573,599, issued Apr. 6, 1971 illustrates an isolated circuit using a voltage regulator, and U.S. Pat. No. 3,562,729, issued Feb. 9, 1971 discloses another two wire circuit for temperature sensing.